Use url.path |> Path.toAbsolute in the Pages.PageUrl.toUrl function

[tad-lispy]

I believe on line 35 it should be url.path |> Path.toAbsolute, not toRelative.

https://github.com/dillonkearns/elm-pages/blob/132430b4473ae58986eb2a59650d86482811ba14/src/Pages/PageUrl.elm#L30-L38

Otherwise with --base=/prefix/ CLI option a function like below would produce something like https://example.comprefix (without a slash between the host name and the path).

baseUrl : PageUrl -> String
baseUrl url =
    { url
        | path = Route.Index |> Route.toPath
        , query = Nothing
        , fragment = Nothing
    }
        |> Pages.PageUrl.toUrl
        |> Url.toString

Arguably it's wrong of Url.toString from the elm/url package to produce this kind of output. Maybe it should insert the slash if there isn't one in the path field of the Url record. But I suspect we have a better chance of fixing it here in any reasonable time ;-)